Research and design of photovoltaic cells simulator by polynomial fitting

The mathematical model of photovoltaic cells is analyzed and a simplified mathematic model for engineering application is offered,which only needs five rated parameters to completely represent its external features with engineering precision.Four-segment broken-line is applied to precisely fit the I-U characteristic curve of photovoltaic cells and a digital photovoltaic cells simulator is then designed based on the characteristic curve by polynomial fitting.Its main circuit is a Boost converter controlled by a current-loop PI regulator.Simulative and experimental results show that its model error is below 6 %,meeting the design and simulation accuracy of photovoltaic cells system.